这是主文件：
// ConsoleApplication7.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "targetver.h"
//void __video_encode_example(const char *filename);
int _tmain(int argc, _TCHAR* argv[])
{
//__video_encode_example("adi.avi");
return 0;
}
我尝试使用以下方法调用该函数：
void __video_encode_example(const char *filename);
__video_encode_example("adi.avi");
但我遇到了一些错误。
这是我试图调用它的内部函数的类：
#define FF_API_AVCODEC_OPEN 1
#ifdef __cplusplus
extern "C"
#include "libavcodec\avcodec.h"
#include "libavutil\mathematics.h"
void video_encode_example(const char *filename)
{
AVCodec *codec;
AVCodecContext *c= NULL;
int i, out_size, size, x, y, outbuf_size;
FILE *f;
AVFrame *picture;
uint8_t *outbuf;
int n;
printf("Video encoding\n");
/* find the mpeg1 video encoder */
codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
if (!codec) {
fprintf(stderr, "codec not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
picture= avcodec_alloc_frame();
/* put sample parameters */
c->bit_rate = 400000;
/* resolution must be a multiple of two */
c->width = 352;
c->height = 288;
/* frames per second */
//c->time_base= (AVRational){1,25};
c->time_base.num=1;c->time_base.den=25;
c->gop_size = 10; /* emit one intra frame every ten frames */
c->max_b_frames=1;
c->pix_fmt = PIX_FMT_YUV420P;
/* open it */
if (avcodec_open(c, codec) < 0) {
fprintf(stderr, "could not open codec\n");
exit(1);
}
//f = fopen(filename, "wb");
n = fopen_s(&f,filename, "wb");
if (!f) {
fprintf(stderr, "could not open %s\n", filename);
exit(1);
}
/* alloc image and output buffer */
outbuf_size = 100000;
outbuf = (uint8_t*)malloc(outbuf_size);
/* the image can be allocated by any means and av_image_alloc() is
* just the most convenient way if av_malloc() is to be used */
//av_image_alloc(picture->data, picture->linesize,
// c->width, c->height, c->pix_fmt, 1);
picture->data[0] = (uint8_t*)av_malloc(1000000);
picture->data[1] = (uint8_t*)av_malloc(1000000);
picture->data[2] = (uint8_t*)av_malloc(1000000);
picture->data[3] = (uint8_t*)av_malloc(1000000);
picture->data[4] = (uint8_t*)av_malloc(1000000);
picture->data[5] = (uint8_t*)av_malloc(1000000);
picture->data[6] = (uint8_t*)av_malloc(1000000);
picture->data[7] = (uint8_t*)av_malloc(1000000);
/* encode 1 second of video */
for(i=0;i<25;i++) {
fflush(stdout);
/* prepare a dummy image */
/* Y */
for(y=0;y<c->height;y++) {
for(x=0;x<c->width;x++) {
picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
}
}
/* Cb and Cr */
for(y=0;y<c->height/2;y++) {
for(x=0;x<c->width/2;x++) {
picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
}
}
/* encode the image */
out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
printf("encoding frame %3d (size=%5d)\n", i, out_size);
fwrite(outbuf, 1, out_size, f);
}
/* get the delayed frames */
for(; out_size; i++) {
fflush(stdout);
out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
printf("write frame %3d (size=%5d)\n", i, out_size);
fwrite(outbuf, 1, out_size, f);
}
/* add sequence end code to have a real mpeg file */
outbuf[0] = 0x00;
outbuf[1] = 0x00;
outbuf[2] = 0x01;
outbuf[3] = 0xb7;
fwrite(outbuf, 1, 4, f);
fclose(f);
free(outbuf);
avcodec_close(c);
av_free(c);
av_free(picture->data[0]);
av_free(picture);
printf("\n");
#endif
问题是如何在 main 中声明和使用函数？
现在，如果我编译它，我没有任何错误，但是当我尝试在 main 中调用和使用该函数时，我遇到了一些错误。
编辑
这是我在尝试在 main 中声明和调用函数时遇到的错误：
错误 1 错误 LNK2019：函数 wmain 中引用的未解析外部符号“void __cdecl __video_encode_example(char const *)”(?__video_encode_example@@YAXPEBD@Z)
和：
错误 2 错误 LNK1120: 1 未解决的外部
我没有添加任何标题或其他内容，这是具有上述函数的类，这就是我尝试从类中声明和调用函数的方式。